We present radial properties of X-ray emitting gas in about
15 galaxy groups and clusters derived from CHANDRA data,
with emphasis on their entropy distributions. Only relaxed
systems are chosen for our study, excluding systems with
mergers or with significantly disturbed gas cores. It is
found that the inner entropy profiles of galaxy groups are
flatter than predicted from simulations and flatter than the
inner entropy profiles of hot clusters with cooling cores.
Clusters with isentropic cores are also found. Variations
are found in the inner entropy profiles of these systems,
which reflect differences in the physical states of their
gas cores. Gas temperature and abundance profiles are also
presented and discussed.